In this talk, I will describe a solvent-perturbed transition state (SPTS) sampling scheme for simulating chemical reaction dynamics in condensed phase. The method, adapted from Truhlar and Gao’s ensemble-averaged variational transition state theory, includes the effect of instantaneous solvent configuration on the potential energy surface of the reacting system (RS), and allows initial conditions for the RS to be sampled quasiclassically by TS normal mode sampling. We used a QM/MM model with direct dynamics, in which QM forces of the RS are computed at each trajectory point. The SPTS scheme was applied to the acceleration of the Diels-Alder reaction of cyclopentadiene (CP) + methyl vinyl ketone (MVK) in water. The results show that water molecules reorient to form enhanced hydrogen bonds with carbonyl oxygen from reactant to transition state. We also explored rebound oxidation reactions in acetone solvent. The non-statistical dynamics of C-H hydroxylation by dioxirane was observed, which account for the high stereoselectivity of such reactions.

QM/MM protocol for direct molecular dynamics of chemical reactions in solution: The water-accelerated Diels-Alder reaction and rebound oxidation reactions

251st National Meeting (2016)

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